Twenty aporphine derivatives structurally related to apomorphine have been synthesized. (minus)2,10,11-Trihydroxy-N-n-propylnoraporphine (TNPA-2-OH-NPA) prepared from thebaine, showed anticonvulsant activity comparable to its 10,11-dihydroxy counterpart (NPA) on the stimulation of DA-sensitive adenylate cyclase in carp retinal homogenates. The evaluation of TNPA on audiogenic seizures in mice, in the protection against paroxysimal EEG and myoclonic response to photic stimulation in the baboon, revealed a similar pharmacological profile in comparison to NPA and apomorphine with TNPA showing a prolonged duration of action in obtaining myoclonic response to photic stimulation in the babbon. These findings support the suggestion that dopamine plays an important role in the pathophysiology of photically-induced seizures in man and animals. The observation that dopamine agonists block the reflex induction of a variety of seizure phenomena further suggest the potential utility of such DA agonists as NPA and TNPA in therapy. The activity of these and related trihydroxylated aporphines were evaluated against the high-affinity (nM) binding of H3-APO and H3-spiroperidole to sub-synaptosomal membrane preparations of bovine caudate nucleus tissue compared with both mono- and dihydroxylated aporphines.